The present invention relates generally to trailer braking systems and, more particularly, to an apparatus for actuating a trailer brake when a trailer, mounted to a pulling vehicle, becomes detached from the pulling vehicle as the trailer is being pulled.
Trailer breakaway brake actuating mechanisms are known in the art. These mechanisms generally operate through a cable or chain, which is attached to a pulling vehicle by means of an S-hook or similar attachment device. The opposite end of the cable is operably connected to the trailer's braking system so that the trailer brake is actuated when the cable is pulled. When the trailer becomes detached from the pulling vehicle during operation, the trailer, no longer being pulled, tends to change position relative to the pulling vehicle. The S-hook, however, remains attached to the pulling vehicle. As the pulling vehicle pulls the cable, the cable actuates the trailer brake mechanism thereby stopping the trailer. As the trailer stops, the force on the cable increases until the S-hook straightens, fails, and releases the cable from the pulling vehicle. To maintain pressure on the cable and prevent the cable from releasing the trailer braking mechanism, a friction lock is generally used to prevent the cable from retracting and prematurely releasing the trailer brake. Although such mechanisms are generally adequate to stop a breakaway trailer in most circumstances, they do possess several inherent drawbacks.
Most prior art systems operate by means of a friction lock to prevent the extended cable from retracting. During connection and deconnection of the trailer to the pulling vehicle the cable is often pulled toward the pulling vehicle. Even a slight tug is often enough to actuate the breakaway mechanism slightly, or to cause dangerous slack in the cable when the friction lock prevents the cable from returning taught after connection to the pulling vehicle. Even though the brake mechanism may be actuated only somewhat, this slight activation can cause excessive wear on the trailer brake and an excessive burden on the pulling vehicle which decreases fuel mileage and increases maintenance costs. Over time this excessive burden could even cause the trailer brake to fail in an emergency situation due to premature lining wear or overheating.
Another problem with existing trailer breakaway brake actuators is that friction locks are generally provided on the surface of the trailer mount housing. While this surface mounting aids in deactivating the lock, the surface placement exposes the lock to the elements which may wear or even clog the braking mechanism thereby often rendering the mechanism ineffective and unsafe.
The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention.